They pointed out that there is concern about the oil demand due to the slowing economies of some developing countries and trade wars caused by President Donald Trump, but the impact of these factors on the oil market will not appear before next year.
U.S. West Texas Intermediate (WTI) crude was down 28 cents, or 0.4 percent, to $68.62 per barrel. Washington aims to cut Iran oil exports down to zero to force Tehran to re-negotiate a nuclear deal. Russia, the world's largest oil producer, and other producers in OPEC have kept in place a supply agreement to maintain prices while at the same time providing enough oil to the market.
But supporting crude futures were potential supply cuts from USA sanctions on Iran.
Brent oil traded near the highest level in a week after Saudi Arabia was said to be content with the global benchmark crude breaking above $80 a barrel.
The trade dispute is raising concerns about the potential for slower growth in oil consumption, offsetting supply concerns stemming from the upcoming USA sanctions on Iran over its nuclear program.
On the supply side, ahead of the US crude sanctions against Iran in November, the oil producer has decreased its export loadings by 580,000 barrels per day in the past three months, according to analysts at the Bank of America Merrill Lynch (NYSE:BAC).
The tariffs are likely to limit economic activity in both China and the United States.
A leading Iranian official said on Saturday that Saudi Arabia and Russian Federation had taken the oil market "hostage" and accused other producers of turning the Organization of the Petroleum Exporting Countries into "a US tool".
LONDON-Oil prices advanced on Monday on the back of a weaker dollar and continued expectations of a global supply crunch.
The head of OPEC said Tuesday that Iran remains "a very important member" of the oil cartel, as Tehran braces for a new round of U.S. sanctions partially targeting its crude exports.
The U.S. Energy Information Administration said on Monday that the country's oil output from its seven major hale formations is expected to rise by 79,000 per day to 7.6 million bpd next month.
Prices pared gains in post-settlement trade after data from industry group the American Petroleum Institute showed US crude inventories rose by 1.2 million barrels in the week to September 14 to 397.1 million, compared with analysts' expectations for a decrease of 2.7 million barrels.